Low-Loss Co₂-Y Ferrites with Added CuO Sintered in Air for High Frequency Application

Abstract

The sintering characteristics of hexagonal Co 2 -Y-type ferrite, Ba 2 Co 2 Fe 12 O 22 , with the addition of 0.6 wt% CuO, were studied in order to allow for preparation in air, as opposed to the convention ally recommended O 2 , for industrial production. The dependence of the resistivity, ρ magnetic loss, tan δ , and the permeability, μ , at 1 GHz on the sintering temperature was investigated. A low tan δ of 0.05 with a m of 2.7 at a frequency of 1 GHz, along with a high ρ (up to 7 × 10 4 μ m), were attained under sintering at 1170 °C in air, which were the same features as those of samples sintered at 1200°C in O 2 . The dependence of tan δ on grain diameter was also examined, and it was determined that a small grain size (less than 2 μ m) is preferable for low tan δ .